On Tue, May 31, 2022 at 11:54 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> On 2022-May-31, Peter Geoghegan wrote:
> > This includes a patch from me, to make pruning more robust. It could
> > technically be a bug in my patch, though a bug revealed by my patch
> > seems quite possible too.
>
> Ah, I see. Well, the explanation that depends on Xmin doesn't apply to
> this case. I'm not saying there are no bugs in the other two commits,
> just that such bug(s) have a different explanation, so it makes sense to
> revert separately.
The assertion failure takes place in heapam_index_build_range_scan(),
at the point that it is called by amcheck itself -- during an
opportunistic prune that occurs in passing. This is the specific
assertion that fails:
https://github.com/x4m/postgres_g/blob/09d76bdc2528b476ef2f04c793061dcbf23372b5/src/backend/access/heap/pruneheap.c#L762
Another bug in HEAD definitely seems possible here, but it's hard to
know without careful testing. The failure that we see is limited to
the "macOS - Monterey" run, which only fails on this new test.
--
Peter Geoghegan